Temporal Data Modeling and Reasoning for Information Systems

Temporal knowledge representation and reasoning is a major research field in Artificial Intelligence, in Database Systems, and in Web and Semantic Web research. The ability to model and process time and calendar data is essential for many applications like appointment scheduling, planning, Web services, temporal and active database systems, adaptive Web applications, and mobile computing applications. This article aims at three complementary goals. First, to provide with a general background in temporal data modeling and reasoning approaches. Second, to serve as an orientation guide for further specific reading. Third, to point to new application fields and research perspectives on temporal knowledge representation and reasoning in the Web and Semantic Web

Temporalized logics and automata for time granularity

Suitable extensions of the monadic second-order theory of k successors have been proposed in the literature to capture the notion of time granularity. In this paper, we provide the monadic second-order theories of downward unbounded layered structures, which are infinitely refinable structures consisting of a coarsest domain and an infinite number of finer and finer domains, and of upward unbounded layered structures, which consist of a finest domain and an infinite number of coarser and coarser domains, with expressively complete and elementarily decidable temporal logic counterparts. We obtain such a result in two steps. First, we define a new class of combined automata, called temporalized automata, which can be proved to be the automata-theoretic counterpart of temporalized logics, and show that relevant properties, such as closure under Boolean operations, decidability, and expressive equivalence with respect to temporal logics, transfer from component automata to temporalized ones. Then, we exploit the correspondence between temporalized logics and automata to reduce the task of finding the temporal logic counterparts of the given theories of time granularity to the easier one of finding temporalized automata counterparts of them.Comment: Journal: Theory and Practice of Logic Programming Journal Acronym: TPLP Category: Paper for Special Issue (Verification and Computational Logic) Submitted: 18 March 2002, revised: 14 Januari 2003, accepted: 5 September 200

Reading the City, Walking the Book: Mapping Sydney's Fictional Topographies.

This thesis locates itself on the double ground of Sydney’s fictional and material topographies. My purpose is to read and write the city’s spatio-temporal dimensions through four novels: Christina Stead’s Seven Poor Men of Sydney (1934), M. Barnard Eldershaw’s Tomorrow and Tomorrow and Tomorrow (1947), Patrick White’s The Vivisector (1970) and David Ireland’s City of Women (1981). Deploying a hybrid methodology informed by critical and creative approaches to the city in literature and modernity, the thesis investigates the manifold ways in which the novels draw on Sydney’s topographies to shape and structure their narratives spatially, not only in an abstract and symbolic sense but through the materiality of urban places. Each novel I argue, offers new perspectives on the relationships between text, place and writer. My approach and methodologies draw on J. Hillis Miller’s work on literary topographies, particularly novelistic creations of figurative maps. This textual approach is complemented by Walter Benjamin’s conceptualisation of the modern city as a landscape to be read critically with a ‘topographical consciousness’ which I interpret as a set of modes for reading the city as text and the text as city. Intertwined with these literary and material approaches is an ‘on the ground’ methodology for ‘walking the book’. Influenced by Benjamin’s ‘art of straying’, the Surrealists and the Situationists, I reconceptualise the dérive or urban drift as a critical and creative practice for literally and figuratively walking fictional and material Sydney. Through reading the city and walking the book I conclude, familiar urban spaces are imaginatively and critically opened up as past, present and future, the fictional and the material, collide and re-assemble into new configurations: alternative cartographies

Encapsulating deontic and branching time specifications

In this paper, we investigate formal mechanisms to enable designers to decompose specifications (stated in a given logic) into several interacting components in such a way that the composition of these components preserves their encapsulation and internal non-determinism. The preservation of encapsulation (or locality) enables a modular form of reasoning over specifications, while the conservation of the internal non-determinism is important to guarantee that the branching time properties of components are not lost when the entire system is obtained. The basic ideas come from the work of Fiadeiro and Maibaum where notions from category theory are used to structure logical specifications. As the work of Fiadeiro and Maibaum is stated in a linear temporal logic, here we investigate how to extend these notions to a branching time logic, which can be used to reason about systems where non-determinism is present. To illustrate the practical applications of these ideas, we introduce deontic operators in our logic and we show that the modularization of specifications also allows designers to maintain the encapsulation of deontic prescriptions; this is in particular useful to reason about fault-tolerant systems, as we demonstrate with a small example.Fil: Castro, Pablo Francisco. Universidad Nacional de Río Cuarto; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Maibaum, Thomas S. E.. Mc Master University; Canad

The 101 translation problems between Japanese and German/English

We investigate differences between Japanese and German/English and explain characteristic phenomena to Japanese. The study helps us to realize what can be problematic when translating Japanese into German/English and vice versa

Reasoning about history based access control policy using past time operators of interval temporal logic

Interval Temporal Logic (ITL) is a flexible notation for the propositional and first-order logical reasoning about periods of time that exist in specifications of hardware and software systems. ITL is different from other temporal logics since it can deal with both sequential and parallel composition and provides powerful and extensible specification and verification methods for reasoning about properties such as safety, time projection and liveness. Most imperative programming constructs can be seen as ITL formula that form the basis of an executable framework called Tempura that is used for the development and testing of ITL specifications.\\ ITL has only future operators, but the use of past operators make specifications referring to history more succinct; that is, there are classes of properties that can be expressed by means of much shorter formulas. What is more, statements are easier to express (simplicity) when past operators are included. Moreover, using past operators does not increase the complexity of interval temporal logic regarding the formula size and the simplicity. This thesis introduces past time of interval temporal logic where, instead of future time operators Chop, Chopstar, and Skip, we have past operators past Chop, past Chopstar and past Skip. The syntax and semantics of past time ITL are given together with its axiom and proof system. Furthermore, Security Analysis Toolkit for Agents (SANTA) operators such always-followed-by and the strong version of it has been given history based semantics using past time operators. In order to evaluate past time interval temporal logic, the problem of specification, verification of history based access control policies has been selected. This problem has already been solved using future time of interval temporal logic ITL but the drawback is that policy rules are not succinct and simple. However, the use of past time operators of ITL produces simple and succinct policy rules. The verification technique used to proof the safety property of history based access control policies is adapted for past time ITL to show that past time operators of interval temporal logic can specify and verify a security scenario such as history based access control policy

Extraction of objects from legacy systems: an example using cobol legacy systems

In the last few years the interest in legacy information system has increased because of the escalating resources spent on their maintenance. On the other hand, the importance of extracting knowledge from business rules is becoming a crucial issue for modern business: sometime, because of inappropriate documentation, this knowledge is essentially only stored in the code. A way to improve their use and maintainability in the present environment is to migrate them into a new hardware / software platform reusing as much of their experience as possible during this process. This migration process promotes the population of a repository of reusable software components for their reuse in the development of a new system in that application domain or in the later maintenance processes. The actual trend in the migration of a legacy information system, is to exploit the potentialities of object oriented technology as a natural extension of earlier structured programming techniques. This is done by decomposing the program into several agent-like modules communicating via message passing, and providing to this system some object oriented key features. The key step is the "object isolation", i.e. the isolation of .groups of routines and related data items : to candidates in order to implement an abstraction in the application domain. The main idea of the object isolation method presented here is to extract information from the data flow, to cluster all the procedures on the base of their data accesses. It will examine "how" a procedure accesses the data in order to distinguish several types of accesses and to permit a better understanding of the functionality of the candidate objects. These candidate modules support the population of a repository of reusable software components that might be used as a basis of the process of evolution leading to a new object oriented system reusing the extracted objects

Time granularity in simulation models within a multi-agent system

The understanding of how processes in natural phenomena interact at different scales of time has been a great challenge for humans. How information is transferred across scales is fundamental if one tries to scale up from finer to coarse levels of granularity. Computer simulation has been a powerful tool to determine the appropriate amount of detail one has to impose when developing simulation models of such phenomena. However, it has proved difficult to represent change at many scales of time and subject to cyclical processes. This issue has received little attention in traditional AI work on temporal reasoning but it becomes important in more complex domains, such as ecological modelling. Traditionally, models of ecosystems have been developed using imperative languages. Very few of those temporal logic theories have been used for the specification of simulation models in ecology. The aggregation of processes working at different scales of time is difficult (sometimes impossible) to do reliably. The reason is because these processes influence each other, and their functionality does not always scale to other levels. Thus the problems to tackle are representing cyclical and interacting processes at many scales and providing a framework to make the integration of such processes more reliable. We propose a framework for temporal modelling which allows modellers to represent cyclical and interacting processes at many scales. This theory combines both aspects by means of modular temporal classes and an underlying special temporal unification algorithm. To allow integration of different models they are developed as agents with a degree of autonomy in a multi-agent system architecture. This Ecoagency framework is evaluated on ecological modelling problems and it is compared to a formal language for describing ecological systems